12-17 20:28:42.115 18003-18003/com.kashikoma.memo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.kashikoma.memo, PID: 18003
java.lang.NullPointerException: Attempt to invoke virtual method 'android.support.v4.app.FragmentTransaction android.support.v4.app.FragmentManager.beginTransaction()' on a null object reference
at com.kashikoma.memo.MemoAdapter$1.onClick(MemoAdapter.java:45)
at android.view.View.performClick(View.java:4799)
at android.view.View$PerformClick.run(View.java:19938)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5384)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:702)
該当コード
エラーの該当部分は OnBindViewHolder > OnClick内 です。
public class MemoAdapter extends RealmRecyclerViewAdapter<Memo, MemoAdapter.MemoViewHolder> {
private OrderedRealmCollection<Memo> mDataset;
MemoAdapter(OrderedRealmCollection<Memo> memoDataset) {
super(memoDataset, true);
this.mDataset = memoDataset;
setHasStableIds(true);
}
@Override
public MemoViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.listitem_memolist, parent, false);
return new MemoViewHolder(view);
}
@Override
public void onBindViewHolder(final MemoViewHolder holder, final int position) {
final Memo obj = getItem(position);
holder.memo.setText(obj.getMemo());
holder.id.setText(obj.getId());
// アイテムクリックされたら編集画面へ
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final String id = obj.getId();
Bundle bundle = new Bundle();
bundle.putString("id", id);
EditMemoFragment fragment = new EditMemoFragment();
fragment.setArguments(bundle);
fragment.getFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
}
});
}
@Override
public int getItemCount() {
return mDataset.size();
}
static class MemoViewHolder extends RecyclerView.ViewHolder {
TextView memo;
TextView id;
MemoViewHolder(View view) {
super(view);
memo = view.findViewById(R.id.memoContent);
id = view.findViewById(R.id.memoId);
}
}
}
関連コード
・メインアクティビティ
public class MemoListActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_memolist);
if (findViewById(R.id.container) != null) {
if (savedInstanceState != null) {return;}
TaskListFragment firstFragment = new TaskListFragment();
firstFragment.setArguments(getIntent().getExtras());
getSupportFragmentManager().beginTransaction().add(R.id.container, firstFragment).commit();
}
//ボトムナビゲーション
BottomNavigationView bottomNavigationView = (BottomNavigationView)
findViewById(R.id.bottom_navigation);
bottomNavigationView.setOnNavigationItemSelectedListener(
new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.action_memo: {
MemoListFragment fragment = MemoListFragment.newInstance();
getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
return true;
}
case R.id.action_task: {
...
}
}
return false;
}
});
//Realm初期化・アプリ起動時のActivityに記述
Realm.init(this);
RealmConfiguration config = new RealmConfiguration.Builder().build();
Realm.setDefaultConfiguration(config);
}
}
```
・containerに表示されるフラグメント(onCreateView内でアダプタがnewされている)
```ここに言語を入力
public class MemoListFragment extends Fragment {
private FloatingActionButton fab;
private MemoListActivity memoListActivity;
private RecyclerView recyclerView;
private Realm realm;
private MemoAdapter adapter;
public static MemoListFragment newInstance(){
MemoListFragment f = new MemoListFragment();
Bundle args = new Bundle();
f.setArguments(args);
return f;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_memo_list, container, false);
fab = view.findViewById(R.id.intentEditMemo);
realm = Realm.getDefaultInstance(); // Realmをインスタンス化
final RealmResults<Memo> result = realm.where(Memo.class).findAll() // テーブルから全レコード取得
.sort("id", Sort.DESCENDING);// 降順にソート
adapter = new MemoAdapter(result); // その結果をアダプターに渡す
recyclerView = view.findViewById(R.id.memoList);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(adapter);
recyclerView.setHasFixedSize(true);
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL));
return view;
}
@Override
public void onStart() {
super.onStart();
//新規作成ボタン
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Bundle bundle = new Bundle();
bundle.putString("id", "");
EditMemoFragment fragment = new EditMemoFragment();
fragment.setArguments(bundle);
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.container, fragment.newInstance(),"EditMemoFragment").commit();
}
});
}
@Override
public void onDestroy() {
super.onDestroy();
recyclerView.setAdapter(null);
realm.close();
}
}
```
Q&A
ベストアンサー
バッドをするには、ログインかつ
こちらの条件を満たす必要があります。
2019/12/19 03:11
2019/12/19 03:30 編集
2019/12/19 07:04
2019/12/19 13:08
2019/12/19 14:10
2019/12/19 14:21 編集
2019/12/20 09:12
2019/12/20 09:30
2019/12/20 11:46
2019/12/20 12:26
2019/12/20 12:35 編集
2019/12/20 12:35
2019/12/20 14:04
2019/12/21 05:36 編集
2019/12/21 05:44
2019/12/21 05:46
2019/12/21 08:09
2019/12/21 08:29 編集
2019/12/21 08:58